Amos Dudley, a broke undergrad, casted a mold of his teeth using "cheap alginate powder, Permastone, and a 3d printed impression tray," then 3D printed and vacuformed a series of alingment trays for a fraction of what it would have cost to get name-brand invisaligns.
Obviously, this only works if you have ready access to "knowledge of orthodontic movement, a 3D scanner, a mold of the teeth, CAD software, a hi-res 3D printer, retainer material, and a vacuum forming machine."
But if you do, it doesn't look all that challenging to roll your own alignment trays.
Interestingly enough, a fight over precisely this kind of thing may destroy the Internet.
So what does one need to do this themselves? Knowledge of orthodontic movement, a 3D scanner, a mold of the teeth, CAD software, a hi-res 3D printer, retainer material, and a vacuum forming machine. I realized, I had – or could acquire – all of these things. I have my own 3D printer, but the dimensional accuracy isn't good enough. NJIT has a digital fabrication lab with a Stratasys Dimension 1200es. That would do the trick. I tested the machine, and found it could give me X,Y accuracy under .1mm, which was close enough. I think a stereolithography printer like a Formlabs Form2 would have been even better, since they have vast X,Y resolution and accuracy. Vertical print resolution didn't matter much- the direction of motion was in X and Y, not Z. The same lab also has a vacuum forming machine, and some NextEngine laser scanners.
Orthoprint, or How I Open-Sourced My Face